For Us
by TheMadKatter13
Summary: [Commission 03] "Either we fuck, or we're done." Canon Divergence, Top John / Bottom Sherlock


**It's almost funny how different this fic is from the last time I wrote ace Sherlock, but that's the beauty of fanfic… :3**

 **Commission for the lovely addignisherlock (tumblr) / angstlover (AO3)**

 **Betaed by the lovely Sexxica and starrysummernight (both AO3).**

 **Cross-posted from AO3 same-day.**

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Sherlock had nearly gone to bed early for once. No cases on, no research he had to conduct nor felt the pressing need to, John off to the pub with strict demands not to text unless Sherlock was experiencing "an _actual_ emergency, I swear to god if you make up one more thing to interrupt one of my nights out-". Instead, he'd curled up in his chair and retreated into his mind palace. He wished he hadn't. He wished he'd been sleeping when John had come home so that he wouldn't have had to see the transgressions writ over his clothes, his skin. His sleep would have been deep enough for John to shower, to hide his clothes, the evidence, so that Sherlock could remain willfully ignorant a bit longer.

 _"I know you believe John to be different than the rest of humanity, and perhaps he is, with you, but in this, he will not be. He will not understand. He will betray you."_

Sherlock had stolen three of Mycroft's credit cards for that little visit and given them and their pins to his Irregulars.

He had been right, though. In the end, he had been right. Mycroft was almost always right, even when Sherlock didn't want him to be. Especially when Sherlock didn't want him to be.

John was wavering drunkenly in the doorway, his expression loose in that just-had-sex sort of way. Not a wank. Sex. _"Going down to the pub for some drinks with a mate."_ he'd said. Sherlock had known who he'd meant; John had been returning to his more military habits for weeks, had been emailing frequently in his little search-and-peck typing way, had been on the phone with someone not Harry.

Major James Sholto. Former commander. Former lover. Former… nothing. Not anymore. Just… 'current'.

Sherlock had never met the man, but he could still see phantom hands in John's clothes and hair, lips against his neck and cock, John's cock… John's cock in someone else. The knowledge struck him like lightning, freezing him where he sat, obliterating his insides. John hadn't moved yet either, except where he kept periodically slumping then straightening and bouncing off the door frame.

"I thought you were different." Despite feeling like he'd suddenly gone hollow, his words came out normal, unaffected by the emotional blow he'd just been dealt. Because he'd truly believed John was different than those who had come before him, the scant few boyfriends he'd tried to open up to in every way except the way they couldn't accept that he couldn't. Sex was simply too important for the modern male, even John. Especially John.

He'd blinded himself to the facts for weeks, been willfully ignorant of the signs. He'd left John alone when he'd gone to his room to wank, even though he had been disappearing to do just that more and more frequently. He hadn't acknowledged the way John had started touching him, not inappropriately, just putting a hand on his waist, or his forearm, the back of his neck, but the touches had been warm, firm, lingering. He had never responded when John had started reminiscing over his past sexual escapades, voice fond and nostalgic. It had all been right there in his face, and he hadn't paid them one whit of attention.

"Different?" John echoed, voice slurred. Then he snorted. "'Course I'm different." He took a slow, measured step forward into the flat, hand gripping the doorknob to keep himself from wobbling off course. Then he took another one, wobbling slowly but surely into the room and closer to Sherlock.

"No, you're not. You're just like the rest of them." Sherlock's throat felt dry, but somehow, his voice kept going. Odd, considering his mind felt like it was trapped in sludge. "I made it clear when you moved in that I was asexual. When you told me you loved me, I repeated myself. I made sure you understood that sex holds no interest for me, whether giving or receiving, and you said that that was fine. You said it was fine. You said-" Sherlock snapped his mouth closed, distantly shocked at his own helpless repetition.

Sherlock stood abruptly, the movement apparently quick and sudden enough to startle John into a wavering pause. Sherlock swallowed thickly, ignoring the strange, unwelcome, unpleasant sensation in his throat.

"I thought you understood, and that was my mistake," Sherlock said stiffly, back so straight it was almost uncomfortable. John was nearly close enough to touch now, but Sherlock wanted nothing of the sort. "I won't be making it again. Good night, John."

He moved to step around John, and was startled when the other man's hands shot out and shoved him, making him stumble backwards and trip into his chair. Ignoring the few time Sherlock had provoked John into hitting him, John had never in their relationship raised a hand to him, and the fact that he'd just done so made Sherlock's brain blank with surprise.

"What I _understood_ is that you're a selfish prick," John drawled, shoving at Sherlock's shoulder when he instinctively moved to stand up. He took a step forward between Sherlock's legs, forcing his knees wide. Even with John's short stature, their current positions meant John towered over him, and his drunken gaze was oddly heavy, keeping Sherlock still in his seat. "What I _underestimated_ was _how_ fucking selfish you were." Sherlock opened his mouth to respond, but no words came out. Even if he'd managed, John shoved his shoulder again, forcing him to lean back in the chair, a silent ' _shut up and stay still'_. "I thought you'd at least lend a hand, you know? Touch me. Let me touch you a little. Let me see you. Give me something to get off to. But no. Couldn't fucking have that could you? Can't even bear the thought of me kissing you, can you?"

Sherlock was shaking his head before he'd even thought about it. Just the thought of their genitals… interacting, sent his stomach into freefall and his heart into arrhythmia. He'd tried to get over it, in his youth, before he'd understood what the matter was. Before Mycroft helped him understand that nothing was the matter with him but that too few would think so.

It took him a moment to realize that that had been the exact wrong thing to do, that John had gone so very still and so very quiet. Sherlock's pulse pounded with a flood of adrenaline as he raised his eyes to John's face, and then he flinched away at the absolute _fury_ he found there. Gone was the satiated look, gone was the hard look. In their place was an expression of anger so extreme that it hurt to look at. Sherlock looked down so he wouldn't have to see it, and kept his head down when he stood.

"I'm sorry, John, but I cannot."

John took a step back, out of his way, but then there was a swoosh of movement. Sherlock looked up in time to block the fist that had been swung at him, but John was too close and the movement kept his fist going around the back of his head, knuckles grazing through his hair. He stared down at John in shock, one arm still raised against John's forearm… and stared.

John stared back, and then the fingers of his fist snagged in Sherlock's hair and dragged him down, forcing their lips together in a harsh kiss. John's eyes were too close, still open, still furious. And then Sherlock tried to struggle, shoved at John's chest, but he couldn't muster the strength necessary to disconnect the kiss. The kiss that John refused to let go of. The hand in his hair only got tighter, and then there was a tongue at the seam of his lips, forcing them open, forcing into his mouth.

It battered around his mouth for too long, tracing over his teeth, the insides of his cheeks, over his tongue. Finally, John pulled back, panting, but didn't let go of Sherlock's hair. He didn't go far, his whiskey breath hot and reeking across Sherlock's face.

"Sherlock," John whispered, voice low, "either we fuck, or we're done. Does. That. Compute."

Sherlock couldn't breathe. He couldn't remember how to inhale or exhale. Couldn't remember how to be alive. His heart was pounding in his chest. He wanted to throw up. He… He didn't want to let John go. Because if John left him, if he ended this, he would actually go. He would leave Baker Street, he wouldn't speak to Sherlock again. That would be the end of them. The end of Sherlock and John.

"Okay." He wanted to be sick. He wanted to say no, to convince John that they didn't need _sex_ for a good relationship. But John had grown up with such expectations. He expected it. Sex was a _necessity_ for a good relationship, and if Sherlock wanted to keep a good relationship with John… Well, compromise was the basis of a good relationship, wasn't it? "Okay. Whatever you want." His mouth was dry.

"Prove. It." John's voice was low, harsh. Demanding. "Prove it, now. Prove that you still want us."

So… very… dry. "What do you want me to do?"

John finally released his hair stepped back, the grin on his face… unpleasant. Hungry. Triumphant. "Strip and get on your knees."

"John-"

"Now, Sherlock."

John's tone, his body language, his expression, gave no room for reasoning, or arguing. No room for anything except total obedience. So Sherlock obeyed.

His fingers felt numb as he unbuttoned his shirt, his arms wooden as he removed it. He barely noticed the existence of his legs as he removed socks and shoes, and then his trousers. He never wore pants, and he'd never regretted it before now. But he couldn't be sure if having one more article of clothing before he was bared to John's eyes would have been better or worse - it would have only delayed the inevitable.

Despite the lack of sensation in his limbs, Sherlock felt hyper-aware of the sensations over his skin: the air in 221B making his nipples pebble in the minor chill, the rug and hardwood already hard at work bruising his knees, John's heavy gaze on his soft, uninterested cock. John's cock, however, was far from uninterested when he pulled it out. He ignored the scientific part of his mind that wondered at the correlation between age and refractory period, at the correlation between drinking and arousal. The slang term 'whiskey dick' floated around his mind like a fruit fly.

Sherlock examined it clinically, the above-average girth, the average length, that it was uncircumcised, like his own. John only gave it a cursory stroke before dropping his hands to his sides.

"Well?"

For some reason, Sherlock felt grateful that John didn't expand on what he wanted. It was a ridiculous feeling, especially when Sherlock hated that he needed to do anything at all.

He shuffled forward on his knees, unsure what to do with his hands when he leaned in to lick the red head. John hummed, but said nothing, otherwise silent. Watching. Sherlock did it again, hating the taste on his tongue. Right now, that taste was naught but skin, if a bit musty, but he knew that another taste was sure to follow, one that almost made him gag to think about. So he didn't. He didn't want to think about the possibility of losing John, of what his life might be like afterwards. So he didn't.

He didn't think at all.

Sherlock moved a little closer and took the glans into his mouth, the stretch of his lips around it obscene and terrible as he slid down past the corona to the shaft. It was a foreign sensation to him. Anything regarding genitals was, for him. Except the short period in his life when he was young and woke up hard, erections were, for the most part, foreign to him as well. But the logistics of the act he was performing wasn't.

Without a gag reflex to speak of, he kept sliding down until his nose was pressed against short, blond, curly pubic hair and the head of John's cock was uncomfortable pressure at the back of his throat. He hollowed his cheeks, sucking slightly as he pulled back. His hands were hanging limply at his sides, thumbs barely brushing his thighs. John's were the same, and he wondered how long it would take before they curled in his hair and _took_.

He pulled off entirely, licked the head again, and then, bracing himself, took it back into his mouth. This time, John groaned and his hips jerked forward, fingers twitching as more of his cock slid into his mouth than he was expecting. He barely kept himself from jerking back or coughing, just _willed_ his body to ignore the sensations and pushed all the way down to the base again before drawing back, pushing his tongue up against the underside of the shaft. This time, John hissed and his fingers curled into fists. Sherlock hoped he wasn't doing it wrong.

With hands that shook, he reached out and touched John's wrist with one finger. When John's fingers loosed, Sherlock guided his hand up to his hair. Best to get it over with, and this way, maybe John would take control, take what he needed from Sherlock so Sherlock didn't have to guess, didn't have to be solely implicit in the act. Sex was supposed to involve both parties, after all.

John didn't even hesitate, just gripped Sherlock's hair with both hands this side of too-hard and used his leverage to cant his hips forward, driving his cock into Sherlock's mouth and to the back of his throat with a groan that Sherlock could almost feel. He pulled out quickly, only to do it again, and again, and again, fucking Sherlock's face. When Sherlock dared to look up, John's eyes were closed and his head was tilted back, his expression one of ecstasy. Sherlock closed his eyes.

As he'd anticipated, soon the taste of his skin was joined by a new one, something a bit… salty? Musky? Not exactly pleasant in any case, but somehow, not exactly unpleasant either. But still nothing that he wanted to taste again. Right then, Sherlock realized that John's breaths were shorter, and his pace picked up to something more furious, more intent. The fingers in his hair were gripping him so tightly now that it hurt, and tears pricked at the corner of his eyes, but Sherlock was grateful for the pain. It meant that this would be over soon. Except then, it wasn't.

The cock in his mouth pulled out so suddenly that it left Sherlock disorientated, and then, when he realized that John had been about to come, he flinched, waiting for the shot of semen across his face. It never came. He carefully opened his eyes and was greeted with the sight of John's cock, one hand wrapped tightly around the base. To stay his orgasm, Sherlock realized. And then, with a start, he realized he hadn't even felt John's hand leave his hair. That was… troubling.

"Turn around and bend over."

The command made him jump, equal parts surprise at hearing John's voice after nothing but the slick sounds of his mouth over John's cock and the breathy groans of pleasure, and dread, at realizing that when John said 'fuck', he hadn't simply meant 'oral'.

The numbness hadn't left his limbs, but it didn't erase the sudden knowledge of how sore his knees were, or the fact that he was still soft between his legs. He did as he was told, turning around and bending down to put his palms flat on the floor. He'd never before been worried at having John at his back, always trusting his flatmate, and then his partner, to watch it for him when he was too busy to do it himself. Now he almost felt overwhelmed by how vulnerable his position was, only amplified by the weight of John's gaze against his back.

"Down," John said, the command accompanied by the sound of John kneeling behind him, and of something being pulled from a pocket. Something that crinkled, and something with a lid that cracked so loud in the quiet flat that he cringed. "I said, _down,_ Sherlock."

Sherlock swallowed hard and went down to his elbows, curling his hands together, excruciatingly aware of how his arse was sticking up in the air, like he was presenting himself for John's pleasure. Cold, slick, calloused fingerpads pressed against the ring of his anus, barely slicking the tense muscle before one finger pressed into him. It was a strange sensation, having something enter him where nothing ever had before. He could feel the way it wriggled against his insides before it pulled out and then pushed back in again.

He concentrated on keeping his breath steady, only for the pattern to be interrupted by _two_ fingers pressing into him, stretching him uncomfortably and making his breath catch in his throat. He very carefully kept his muscles loose, knowing from some of his more distasteful cases the danger in resisting this kind of thing. Even though he knew that the doctor in John would never subject him to the kind of pain and tearing Sherlock had seen, even if he was subjecting him to… this.

The entrance of a third finger made his fingers clench white around each other, and it took a moment of staring down at his own hands that he realized they were entangled. Like he was praying. Only Sherlock wasn't a praying man, wasn't a religious one, and never would be. He didn't disentangle his fingers though. It was easier to bear when he had something to hold on to.

John's fingers felt like they were petting his insides, like they were looking… for… something. His prostate, Sherlock realized, and then fervently wished that John wouldn't find it. It was a futile wish, with his body in the hands of a competent doctor. The first brush against the gland made him jerk forward with a breathless cry, and he hated the sparks of pleasure that snapped at his spine. He could almost imagine John's triumphant grin, especially when his fingers took a special interest in rubbing repeatedly against his prostate, their present purpose of stretching him apparently, temporarily, forgotten. He hated the way his cock began to take interests in the proceedings, hardening between his thighs and then lifting away from them. He hated the way it felt _good_.

"Mmm. So you can get hard after all. I'd wondered," John said, almost conversationally, if not for the fierce pleasure in his voice.

Sherlock wouldn't have known how to respond, even if that wasn't the moment that John pulled his fingers out, leaving him with an awful sort of bereftness. He could hear the crinkle of the condom wrapper behind him and tensed, knowing what was coming next and wishing it wouldn't.

For us, he reminded himself. This is all for us.

One hand, the dry one, settled on his waist. He didn't have to guess where the other one was, not when the head of John's cock pressed against his loosened hole and then popped in. He didn't stop, and Sherlock didn't breathe, until body-warmed denim pressed against his arse, hair tickling his skin, prickling it. John's weight settled over his lower back for a long moment, like he'd gone boneless.

"God, you're so fucking tight." John said it like it was praise, like Sherlock was to be rewarded for never having sex. "No one else has ever had you, have they?"

Sherlock shook his head, his hair brushing over his hands. A hand curled in his hair, not the one still on his waist, and for a moment, unreasonably, he thought about the fact that he was going to need to take a shower to get rid of the lube no doubt being smeared along the strands. A second later, his head was yanked back and he gasped at the uncomfortable stretch against his throat.

"No one else has ever had you, have they?" John asked again, voice dark in possessive sort of way. Like he was pleased that Sherlock was well and truly a virgin. Well, _was_ a virgin.

It took Sherlock a moment to remember how to speak. "No, John. You're the first."

John hummed as he released his hard grip in Sherlock's hair, and then his still-wet fingers smoothed a path down Sherlock's spine. He didn't speak again, just gripped Sherlock's waist with both hands, pulled out, and thrust back in. It wasn't gentle, it wasn't easy, but it did slide right over his prostate, and Sherlock hated the way his hips jerked back into John's his body instinctively searching for the that sensation again. For as highly as Sherlock held the belief of mind over matter, it seemed to have no place here.

John grunted and then thrust into him again, setting up a rough pace that had Sherlock gasping at every intrusion, at every slick slide against his prostate. He had no way to combat the unrelenting lightning sparking through his nervous system, no way to ignore how hard he was when every thrust made his cock both throb and bounce against his stomach. But that didn't meant that Sherlock had to stimulate it. If he came on John's cock… Well, there was no helping that, but he had no desire to orgasm, mentally, no matter how badly his body seemed to want it physically. John, thankfully, certainly didn't seem interested in achieving that end in Sherlock, only in himself.

Every one of Sherlock's unintentional moans seemed to spur John on, made John grip tighter around Sherlock's waist, made him fuck harder and faster into Sherlock's hole. The chemical arousal and pleasure in Sherlock's system nearly made the whole situation completely unbearable to his mind. He was doing this for John, for them, not himself, and the thought that he would orgasm despite all of that made him cold on the inside. He hated it, but he couldn't do anything with that hate, that disgust. So he ignored it.

His knees were skidding on the carpet, the skin over his patella feeling hot, like they were on fire. It was an odd contrast to the pleasured-numbness his spine was spreading to the rest of his limbs. And every time he slid, John yanked him back, pulling Sherlock's arse down onto his cock, faster and faster until the only thing that seemed to exist was John's fingers bruising his waist, John's cock bruising his prostate. Their floor bruising his knees.

When John's pants and grunts and thrusts started shortening, coming quicker and quicker, Sherlock closed his eyes as relief rushed through his system. This time, this time he knew that John would orgasm, would end this whole experience. John was fucking him so hard that it felt like his arse was bruising too, and Sherlock could only hope the sensation of bruising was all in his mind. He didn't want the marks to remember this night by, not when his own memory would be damning enough.

John bent over his back, his forehead pressed to the middle of Sherlock's spine as he grunted and jerked, hips spastic as he reached orgasm. Finally. Sherlock stayed still through it, riding it out, mind already reaching for the moment when John would pull out. Only, he didn't. For some reason, he stayed in Sherlock even as the hardness in Sherlock's arse softened, just kept still with his forehead pressed to Sherlock's back, the sweat from his hair dripping down onto Sherlock's dry skin.

Several long, uncomfortable minutes passed with John still pressed up close and in Sherlock before he finally sat back on his heels, finally let go of Sherlock's waist, finally pulled out. Sherlock didn't move, just listened to the sound of a zipper and the shift of fabric as John put himself away. He was still hard himself, and the lack of prostate stimulation left him feeling almost like he was spinning through space. His body was screaming for release, but Sherlock refused to capitulate now that John was no longer in charge of his body.

Behind him, John stood, and then walked around where Sherlock still had his forehead pressed to his interlaced fingers. Even with his eyes clenched shut and his head bowed, Sherlock could still tell John was crouched in front of him, before John's hand even touched his hair, petting through the curls, like he was comforting Sherlock.

"It's better this way, Sherlock," John said, fingers gentle where before they'd only been harsh, without patience. "You'll see. We'll be better this way." He pressed a kiss to Sherlock's crown, lingering for a long moment, before finally pulling away. "It'll be better," he said again, before he finally walked away.

Sherlock followed the trek of his footsteps across the living room and up the stairs to his bedroom, and didn't relax until he heard John's door closing. Not their bedroom, John's. He didn't know if that was better or worse. But it was only then did he let the tension out of his muscles, and it was only then that he let his body fall to the side, curling in on itself on the carpet.

He was still disgustingly hard, his cock a stiff line against his stomach where he had no need or want of it. But he couldn't seem to get it to stop. He kept his eyes closed, carefully kept his mind away from what had just occurred. Because he had made his choice. Just like all the other boyfriends Sherlock had ever tried out, he had been given a choice: fuck or leave. With everyone else, he had chosen 'leave'. With John, he could only chose 'fuck'.

Something pricked at the corners of his eyes again, like when his hair had been held too tightly, and he squeezed his eyes shut even harder, unwilling to shed a tear over the situation. He'd made a choice, afterall. He didn't want to think about what he would do to ensure John never left him, even as he knew he would do anything to keep them together, that he had done 'anything'. He didn't want to think about what parts of himself he would sacrifice to keep the most important relationship he'd ever had. He didn't want to think at all. So he didn't.

FIN

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